Abstract The nonstructural gene 3D of foot-and-mouth disease virus was amplified by polymerase chain reaction (PCR) from the recombinant plasmids T-3D. A point mutation was conducted at the EcoRⅠrestriction site of 3D gene by means of spliced ovelapping extension PCR. The mutated 3D gene was inserted into the pSOC expression plasmid and the T4 bacteriophage recombinant integration plasmids pR to obtain the recombinant plasmids pSOC-3D and pR-3D. The recombinant plasmids were selected and confirmed by PCR screening and EcoRⅠrestriction endonuclease digestion. The expression plasmid pSOC-3D was used to transform E. coli BL21 and the expression product was analyzed by SDS-PAGE. The recombinant integration plasmid pR-3D was transinfected E.coli E2 strain to obtain the recombinant phages T4-3D, and the protein bands could detected by SDS-PAGE and reacted specifically to serum from FMDV-infected animals.
